我是否错过了一个标准API调用,该调用从一个数字中移除尾随的不重要的零?
var x = 1.234000; // to become 1.234
var y = 1.234001; // stays 1.234001
Number.toFixed()和Number.toPrecision()不是我想要的。
我是否错过了一个标准API调用,该调用从一个数字中移除尾随的不重要的零?
var x = 1.234000; // to become 1.234
var y = 1.234001; // stays 1.234001
Number.toFixed()和Number.toPrecision()不是我想要的。
当前回答
你可以试试这个来缩小浮点数
var n = 0.0000;
n = parseFloat(n.toString());
//output n = 0;
// n = 3.14000; --> n = 3.14;
其他回答
如果将它转换为字符串,它将不会显示任何尾随零,因为它是作为数字而不是字符串创建的,所以后面的零就不会存储在变量中。
var n = 1.245000
var noZeroes = n.toString() // "1.245"
在阅读了所有的答案和评论后,我得出了这样的结论:
function isFloat(n) {
let number = (Number(n) === n && n % 1 !== 0) ? eval(parseFloat(n)) : n;
return number;
}
我知道使用eval在某种程度上是有害的,但这帮助了我很多。
So:
isFloat(1.234000); // = 1.234;
isFloat(1.234001); // = 1.234001
isFloat(1.2340010000); // = 1.234001
如果你想限制小数点后的位置,可以使用toFixed()。
let number = (Number(n) === n && n % 1 !== 0) ? eval(parseFloat(n).toFixed(3)) : n;
就是这样。
所以你想
var x = 1.234000; // to become 1.234
var y = 1.234001; // stays 1.234001
没有附加条件,只需尝试Number()。
Var x = 1.234000, //变成1.234 Y = 1.234001, //保持1.234001 x_ =数字(x), y_ =数字(y); y_ console.log(间);
如果我们有一个数字的s字符串表示形式,例如我们可以使用number的.toFixed(digits)方法(或任何其他方法)来获得,那么为了从s字符串中删除不重要的末尾零,我们可以使用:
s.replace(/(\.0*|(?<=(\..*))0*)$/, '')
/**********************************
* Results for various values of s:
**********************************
*
* "0" => 0
* "0.000" => 0
*
* "10" => 10
* "100" => 100
*
* "0.100" => 0.1
* "0.010" => 0.01
*
* "1.101" => 1.101
* "1.100" => 1.1
* "1.100010" => 1.10001
*
* "100.11" => 100.11
* "100.10" => 100.1
*/
replace()中使用的正则表达式解释如下:
In the first place please pay the attention to the | operator inside the regular expression, which stands for "OR", so, the replace() method will remove from s two possible kinds of substring, matched either by the (\.0*)$ part OR by the ((?<=(\..*))0*)$ part. The (\.0*)$ part of regex matches a dot symbol followed by all the zeros and nothing else till to the end of the s. This might be for example 0.0 (.0 is matched & removed), 1.0 (.0 is matched & removed), 0.000 (.000 is matched & removed) or any similar string with all the zeros after the dot, so, all the trailing zeros and the dot itself will be removed if this part of regex will match. The ((?<=(\..*))0*)$ part matches only the trailing zeros (which are located after a dot symbol followed by any number of any symbol before start of the consecutive trailing zeros). This might be for example 0.100 (trailing 00 is matched & removed), 0.010 (last 0 is matched & removed, note that 0.01 part do NOT get matched at all thanks to the "Positive Lookbehind Assertion", i.e. (?<=(\..*)), which is in front of 0* in this part of regex), 1.100010 (last 0 is matched & removed), etc. If neither of the two parts of expression will match, nothing gets removed. This might be for example 100 or 100.11, etc. So, if an input does not have any trailing zeros then it stays unchanged.
更多使用.toFixed(数字)的例子(在下面的例子中使用了字面值“1000.1010”,但我们可以假设变量):
let digits = 0; // Get `digits` from somewhere, for example: user input, some sort of config, etc.
(+"1000.1010").toFixed(digits).replace(/(\.0*|(?<=(\..*))0*)$/, '');
// Result: '1000'
(+"1000.1010").toFixed(digits = 1).replace(/(\.0*|(?<=(\..*))0*)$/, '');
// Result: '1000.1'
(+"1000.1010").toFixed(digits = 2).replace(/(\.0*|(?<=(\..*))0*)$/, '');
// Result: '1000.1'
(+"1000.1010").toFixed(digits = 3).replace(/(\.0*|(?<=(\..*))0*)$/, '');
// Result: '1000.101'
(+"1000.1010").toFixed(digits = 4).replace(/(\.0*|(?<=(\..*))0*)$/, '');
// Result: '1000.101'
(+"1000.1010").toFixed(digits = 5).replace(/(\.0*|(?<=(\..*))0*)$/, '');
// Result: '1000.101'
(+"1000.1010").toFixed(digits = 10).replace(/(\.0*|(?<=(\..*))0*)$/, '');
// Result: '1000.101'
要使用replace()中使用的上述正则表达式,我们可以访问:https://regex101.com/r/owj9fz/1
如果还想处理数字错误,可以使用Intl。NumberFormat或Number.toLocaleString()
new Intl.NumberFormat().format(0.0100) // "0.01"
new Intl.NumberFormat().format(0.010000000000001) // "0.01"
new Intl.NumberFormat().format(0.009999999999999) // "0.01"
console.log((0.0100).toLocaleString()) // "0.01"
console.log((0.010000000000001).toLocaleString()) // "0.01"
console.log((0.009999999999999).toLocaleString()) // "0.01"